The availability of all-silicon-based optoelectronic integrated circuit (OEIC) technology promises to revolutionize the optoelectronic industry and significantly impact a wide range of both military and commercial applications. One such area of impact is multi-chip module interconnectivity. Silicon-based OEICs will not only solve resistivity and high-capacitance problems by replacing electron transport with photons, they will also provide new functionality, such as circuit-level image processing. Silicon-based OEICs will also provide cost inroads to commercial markets, since high-volume silicon processes enjoy economies of scale unparalleled by other electronic or optoelectronic materials technologies. Furthermore, silicon-based OEICs are expected to provide new functionality such as circuit-level image processing.
There are four technologies required to make silicon-based OEICs a reality: (1) detectors; (2) waveguides; (3) modulators and (4) emitters. While there has been considerable progress in the first three areas, a lack of an appropriate silicon-based light-emitting device, particularly a silicon-based laser, has greatly hindered the development of fully integrated silicon-based OEIC technology.
Nd-doped CaF.sub.2 thin films that function as gain mediums are described herein and specifically claimed in co-pending U.S. patent application Ser. No. 07/954,136 (TI-16928). These results are highly significant as stepping stones leading to silicon-based OEICs. However, since light emission from CaF.sub.2 :Nd by electrical pumping has not been achieved so far, an optical source is required to pump CaF.sub.2 :Nd for lasing. A III-V or IV-VI compound like CaAs or ZnSe can be excited by electroluminscence and emit light at appropriate wavelengths to pump CaF.sub.2 :Nd. However, the III-V or IV-VI compounds grown on silicon or CaF.sub.2 are usually too defective for practical use. This, unfortunately, reduces the efficiency of electroluminescence. Additionally, III-V and IV-VI are complex and expensive sources of electroluminescence. It is desirable to use silicon as the light emitting material, instead. However, silicon has indirect bandgap characteristics. This causes the silicon emission efficiencies to be low.
As a result, there is a need for an optical source to pump CaF.sub.2 :Nd for lasing.
There is a need for a compound that is less defective and more efficient than III-IV and II-VI compounds used for electroluminescence.
There is a further need for a simple and cost-effective method and device that uses silicon as a light source for optically pumping CaF.sub.2 :Nd thin films.
Furthermore, there is a need for a Si-based compound that can be used as a light emitting material and that overcomes the indirect bandgap problem and associated low emission efficiencies characteristic of silicon.